Telegraph switching center arrangement



Sept. 22, 1959 R. A. K QLPEK 2,905,745

TELEGRAPH SWITCHING CENTER'ARRANGEMENT INVENTOR. ROBERT A. KOLPEK R. A.KOLPEK 2,905,745 TELEGRAPH swITcHING CENTER ARRANGEMENT 11 Sheets-Sheet2 Sept. 22, 1959 Filved Nov. 29, 1956 Sept. 22, l959. R. A. KOLPEKTELEGRAPH swITcHING- CENTER ARRANGEMENT Filed Nov. 29, 1956 11sheetsI-sheet s Sept. 22, 1959 I R. A. KoLPEK TELEGRAPH SWITCI-IINGCENTER ARRANGEMENT Filed Nov. 29,1956 11 sheets-sheet 4 v OUTGOING ,LINEFINDER R540 LF] COMPARISON 34e) Y fn? CHARACTER NCH POSITION ourolmcslLINE cmculr swITcH FuNcTIoNs INVENTOR.

T A. KOLPEK I BY SFTISNLII/Zmo TELEGRAPH Sept. 22, 1959 R. A. KOLPEKTELEGRAPH SWITCHING CENTER ARRANGEMENT Filed Nov. 29, ,1956

l1 Sheets-Sheet 5 .INVENTOR ROBERT A KOLPEK W12@ @JM/f AITYS- Sept. 22,1959 R. A. KoLPEK TELEGRAPH swITcHING CENTER ARRANGEMENT Filed Nov. 29,195e 11 Sheets-Sheet 6 3. V... @I ma y m Dl l m w. fw N 8 5:22 1 A m 3 EB L 0 Dn E D T om w om@ .S .dm M/ mw 532 f E fw Bm o mw o? f N8 ,65m am6 mmm :Sm

No@ w25: 52x52 :Y QQ wSEzS l twzst f l I 3m @N23 Sept. 22, 1959y R. A.KoLPx-:K v 2,905,745

TELEGRAPH SWITCHING CENTER ARRANGEMENT Filed Nov. 29, 195e 11sheets-sheet v FROM OTHER oureomc UNE CKT' ouTGolNG LINE HNDER LINK 40o|4805 l 4||\ y l Y 345x sEL. sw.

s4|o o @211.9 4|oA E PREcEoENcE REGISTER o l 4|9 INVENTOR. ROBERT A.KOLPEK ATTYS.

Sept. 22, 1959 R. A. KoLPEK 2,905,745

TELEGRAPH swITcHING CENTER ARRANGEMENT Filed Nov. 29, 195e 11sheets-sheet 9 j 8 l5 l 969 9606 INVENTOR. ROBERT A. KOLPEK AT T YS.

Sept. 22, 1959 R. A. KOLPEK TELEGRAPH swITcHING CENTER ARRANGEMENT 11Sheets-Sheet 1=O Filed Nov. 29, 1956 Lrl WGH .Rf-Is. R870 CLUTCHcoNTRoL| CKT. 800

LINE

OUTGOI N G INVENTOR. ROBERT A. KOLPEK FIG.8

f MMM ATTY S.

Sept. 22, 1959 R. A. KoLPEK 2,905,745

TELEGRAPH swITcHING CENTER ARRANGEMENT Filed Nov. 29, 195e 11sheets-sheet 11 ROBERT A. KOLPEK @MMI/ Ams.

TLEGRAPH SWITCHING CENTER.

GEB/[ENT Robert A. K'olpek, Libertyville, Ill., assignor to General fyTelephone Laboratories, Incorporated,.a corporation of DelawareApplication November 29, 1956, Serial No.'625,098

` 7 Claims. (Cl. 178-2) The present invention relates to an automatictelegraph system and particularly to arrangements in message centers ofthe telegraph system for completing connections between message storageunits therein and outgoing lines extending to message destinations andfor controlling transmission of the telegraph message signals over theoutgoing line.

The automatic telegraph system to which the present invention relates isof the nation-wide type disclosed in the copending application ofRichard C. Stiles, Serial No. 260,854, liled December 10, 1951, nowPatent No. 2,805,283, granted on September 3, 1957, including aplurality of geographically located message switching centers which areinter-linked by transmission lines and which serve multiply as messagedistribution points, relay points between transmission lines, and asmessage terminal points. Accordingly, each switching center is providedwith a plurality of incoming and outgoing lines respectively extendingfrom and to other switching centers. In each switching center, eachincoming line is terminated in an incoming line circuit which receivesthe telegraph messages transmitted over the incoming line and perforatesa tape to make a record of the telegraph message. Each outgoing line isterminated in an outgoing line circuit by means of which the outgoingline is seized and through which transmission of the telegraph messagesignals over the outgoing line is controlled. In theswtching centerthere is also provided a plurality of'cr'oss-ofnce units which areaccessible to any one of the incomingline circuits and which have accessto any one of the outgoing line circuits and which is provided withselectively operative equipment for receiving telegraph messages fromany one of the incoming line circuits seized thereto and for perforatinga tape to make Ia record of the telegraph message, whereby thecross-office unit functions in this operation as a message storage unit.Additionally the crossolice unit is controllable for marking itself ascalling to any one of the outgoing liney circuits and for seizing theone of the outgoing line circuits when the line circuit is idle andthereafter operates with the seized outgoing line circuit to transmitthe telegraph message over the outgoing line.

In the above mentioned Stiles application it is disclosed that eachtelegraph message has assigned one of a plural number of transmissionprecedence ratings and a crossoliice unit which is calling to anoutgoing line circuit marks to the outgoing line circuit thetransmission precedence rating of the message stored therein. When thereare two or more cross-office units calling to the same outgoing linecircuit having messages of different transmission precedence ratingstherein, only the calling cross-office unit having stored therein themessage of the highest transmission precedence rating will be permittedto seize the vidle outgoing line circuit. By way of eX- ample, atelegraph message may have a transmission preference rating, proceedingfrom the highest to lowest order of precedence, of: llash precedence,emergency precedence, operational immediate precedence, priority21,905,745 Patented Sept. 22, 1959 precedence, routine precedence, anddeferred precedence; with iive cross-oliice units calling to the sameoutgoing line circuit and having messages therein of the respectivedifferent transmission precedence ratings, the cross-office units willbe permitted to seize the outgoing line circuit in accordance with theprecedence ratings of the messages stored therein and in the orderlisted above.

, lt is an object of the present invention to provide in a telegraphmessage switching center, which is adapted to process a large number oftelegraph messages during any operational period and to transmit thetelegraph message over any one of a larger number of outgoing lines, animproved linking arrangement between cross-oiice message storage umtsand the outgoing line circuits, whereby all of the cross-office units,irrespective of the transmission precedence rating of the messagesstored therein, may be marked as calling to any one of the outgoing linecircuits and only one of the cross-oiiice units of the highestprecedence rating may seize the idle outgoing line circuit.

An additional object of the invention is to provide in a telegraphmessage switching center an arrangement whereby any cross-office unitscalling to a particular outgoing line seizes the group of outgoing linecircuits that includes the corresponding outgoing line circuit and marksthe corresponding outgoing line circuit as called, and in responsethereto linking means completes a connection betwee'nthe called outgoingline circuit and the one of calling cross-oliice units having storedtherein a message of the highest transmission precedence.v

p A V:further object of the invention is to provide an improvedarrangement in a telegraph message switching center `including aplurality of cross-oce message storage'units, a plurality of outgoinglines accessible to the cross-olice v units through correspondingoutgoing line circuitsand a linking arrangement therebetween, wherebyany cross-oce units calling toa particular outgoing line makes apreliminary seizure of the `corresponding outgoing line circuit andmarks tothe outgoing line circuit and to the linking arrangement thetransmission precedence-ratings of the messages storedthereim'the seizedoutgoing, line circuit marks'itself as called to the linking'arrangement, and the linking arrangement finds the called outgoing linecircuit, registers the 'highest of the transmission precedence ratingsmarked` to the outgoing line circuit, searches through the ones of thecross-oliceunits marked as calling and seizes one of the callingcross-olice units having the sametransmission precedence marking as thattransmission precedence registered therein, whereupon the seizedcross-oice unit'is operated to complete a connection to the seizedoutgoing line circuit.

A further object of the invention is to provide in a telegraph switchingcenter of the type described an improved outgoing line circuit which iscontrollable from a crossoiiice unit for performing operations withregard to the linking arrangement in order to complete va connectionwith a calling cross-oce unit and for retransmitting from the seizedcross-oliice unit to a monitor unit associated with the outgoing linecertain message identity information at the same time that the outgoingline circuit transmits certain start-of-message information over theoutgoing line, and is thereafter controlled to retransmit the messagebody information from the cross-ollice unit to the monitor unit 4andover the outgoing line, and is thereafter controlled to 4transmitcertain identity and end-ofmessage information to the monitor unit andover the outgoing line.

An additional object of the invention is to provide in a telegraphswitching center of vthe type described an improved cross-oice unitwhich is controllablek in response to the seizure ofthecalled outgoinngline circuit unit as calling to the linking -arrangement and for markingthe transmission precedence of the message stored therein to the linkingarrangement and in response to seizure by the linking arrangement iscontrolled to complete a connection to the outgoing line circuit.

An additional object of the invention is to provide in a telegraphswitching center of the type described a linking arrangement betweencross-office units and outgoing ine circuits including an outgoing linefinder link having access to a group of outgoing line circuits andconnected back to back to a number of cross-oiice unit assigner linkscorresponding respectively to the number of groups of cross-oliice unitshaving access to the group of outgoing line circuits served by thefinder link, wherein the inder link is controlled by any called one ofthe outgoing line circuits to seize a called one of the outgoing linecircuits and to register the highest transmission of precedence of anymessage directed -thereto and to mark the registered precedence to theassociated cross-oice assigner links and wherein the cross-officeassigner links are controlled by any one of the calling cross-oice unitsassociated therewith in response to the seizure of the correspondingcalled outgoing line circuit by the line finder link to hunt through thecross-office units and to seize the first one thereof having storedtherein a message of a transmission precedence corresponding to thattransmission precedence marked to the cross-chico assigner link by theoutgoing line finder link.

Further features of the invention pertain to the particular arrangementsin the circuits of the telegraph switching center, whereby the aboveoutlined and additional operating features thereof are attained.

The invention, both as to its organization and method of operation,together with further objects and advantages thereof, will be bestunderstood by reference to the following specification taken inconjunction with the accompanying drawings, in which:

Figures 1A and 1B, taken together, show in block form a telegraphswitching center including the outgoing linking arrangement inaccordance wtih the invention;

Figs. 2 to 10, inclusive, show in detail the circuit included in theoutgoing linking arrangement of the in-` vention;

Fig. l1 illustrates the manner in which Figs. 2 to l0 inclusive arejoined to provide a complete operating arrangement; f

Fig. l2 is a table showing the standard telegraph code employed in thecircuits of the switching centers; and

Fig. 13 isa table showing the infomation transmission functions ofvarious switches included in the outgoing line circuits of theinvention.

The general arrangement of the switching center Referring specificallyto Figs. lA and 1B, the switching center there illustrated in blockschematic form is but one of a plurality of such centers in an automatictelegraph switching system serving a large communication area andcorresponds to the switching center disclosed in the copendingapplication to Richard C. Stiles, Serial No. 260,854, filed December 10,1951. The switching center here illustrated is adapted to serve aplurality of telegraph lines incoming thereto and to route telegraphmessages received over the incoming lines to appropriate outgoing linesextending to the message destinations.

Insofar as the switching center of the present invention corresponds tothe switching center disclosed in the above mentioned Stilesapplication, the apparatus and circuit elements common therebetween havebeen given the same titles as used in the Stiles application and thesame identification numerals with the sul-'tix X added thereto.

In the switching center shown in Figs. 1A and 1B there is provided aplurality of incoming line circuits, includ-` ing the incoming linecircuit 400X, each terminating an' individually associated telegraphline, a plurality of crossofce units arranged in groups and includingthe crossofrice unit 3400K and 200, and a plurality of outgoing linecircuits each terminating an outgoing line and arranged in groups andincluding the outgoing line circuit 800. Any one of the outgoing linecircuits in any one of the groups thereof is accessible to any one ofthe crossoice units in any one of the groups thereof.

Each group of outgoing line circuits has associated I' therewith anoutgoing line finder link, such as the outgoing line nder link 400associated with the Group No.`

1 of outgoing line circuits, which has access to any one of the outgoingline circuits in the group, Each group of cross-office units hasassociated therewith a number of cross-office assigner links, such asthe croSS-oliice assigner link 300, corresponding to the number ofgroups of outgoing line circuits to which the group of cross-officeunits have access. Thus, as shown in Fig. 1B, the Group No. l ofcross-oice units has access to Groups No. 1 and No. 2 of outgoing linecircuits and has associated therewith the cross-oflice assigner links300 and 300A both of which have access to any one of the cross-officeunits in the Group No. l, the former being connected back to back to theoutgoing line finder link 400 associated with the Group No. 1 ofoutgoing line circuits and the latter being connected back to back tothe outgoing line finder link 400A associated with the Group No. 2 ofoutgoing line circuits. In a similar manner the crossoice units of GroupNo. 2 which have access to the Groups No. l and No. 2 of outgoing linecircuits, have associated therewith the cross-oice assigner links 300Band 300C both of which have access to any one of the cross-office unitsin the Group No. 2, the former being 1 connected back to back to theoutgoing line finder link 400 and the latter being connected back toback to the outgoing line nder link 400A. Through this arrangement anyone of the outgoing line circuits in the groups thereof, auch, forexample, as the outgoing line circuit Stil),

may be seized to any one of the cross-office units in the Groups No. land No. 2 thereof, such, for example, as the cross-othce unit 200, bymeans of an outgoing line finder link and a cross-oihce assigner linkand, specifically in the examples cited, by means of the outgoing linefinder link 400 and the cross-oice assigner link 300.

" for perforating a tape 333K in accordance with the telegraph messagereceived over the incoming line, a tape reader 340X for sensing theperforations in the tape and forperforming in response thereto certaincontrol functions, and an incoming line retransmitter 360X which visselectively operative for retransmitting the telegraph messageperforatedon the tape 333X. The tape reader 340K and the control circuitsassociated therewith operates the director 200AX to select an idlecross-office unit and 'to identify the outgoing line over which themessage mnst be transmitted in order for it to arrive at itsdestination. Having performed these functions, the directorV ZGOAXoperates the cross-oflice selector 3300K to connect to a selected one ofthe cross-office units and causes the Selected cross-oice unit to havetransmitted thereto the information regarding the identified outgoingline and the transmission precedence of the telegraph message.Thereafter the director 200AX retires from the connections and theincoming line retransmitter 360K is operated to transmit signalscorresponding to the telegraph message perforated in the tape to theselected cross-office unit. Upon completion of transmission of tlitelegraph message, the incoming line circuit 400X and the apparatusassociated therewith is restored to normal 4and prepared to receiveanother telegraph message over the incoming line. 'I'he details of themode of operation of the circuits in the incoming line circuit 400X, thedirector 200AX and cross-oice selector 3300X is set forth in detail inthe above mentioned Stiles application.

' Each cross-office unit, such as the cross-oice unit 3400X, is providedwith apparatus such as that illustrated in Fig. 1B including a supply ofperforating tape 3413K, a tape reperforator 3410K, a tape reader 3420K,an outgoing retransmitter 3430X, an outgoing selector 4300K, and a groupof control circuits. The group of control circuits operates the tapereperforator 3410K in order to perforate the tape 3413X in accordancewith the telegraph message signals received in the cross-othce unit andto operate the outgoing selector 4300X for select-ing the connection tothe designated outgoing line. At the time that the cross-office unit isswitched through to the designated outgoing line the control circuitsare then operated in order to cause the perforated tape to be fedthrough the tape reader 3420K and the outgoing retransmitter 3430X inorder to cause the telegraph message perforated thereon to betransmitted over the outgoing line. Selected portions of the cross-ofhceunit .3400X deemed necessary to a proper understanding of .the inventionis disclosed in the cross-office unit 200 of IFigure 2, and the detailsof the apparatus and method of operation of the cross-oilice unit 3400Xwith regard sthereto will be understood by reference to the aboveLmentioned Stiles application.

Apparatus incorporated in the switching center Referring now to Fig. 2,the cross-oil'ice unit 200 shown in part therein is provided with agroup of relays including a test relay R3S90X, a test relay R3930X, aslave relay R220, a marking relay R225, an auxiliary marking relay R230,and a control relay R3830X. Further, there is included an outgoing lineselector switch S202, a precedence switch S235, and a cross-oi'liceassigner selector switch S245. In addition, there is included a set ofsensing contacts 3490X associated with the outgoing line retransmitterof the Cross-oce unit and a clutch magnet M3425X for operating thesensing contacts 3490K. The outgoing line selector switch S202 is madeup of seven sets of wipers and associated banks of contacts wherein eachset of contacts in the banks are connected via a trunk, such as thetrunk 261, to an individual one of the outgoing line circuits, such asthe outgoing line circuit 800, and the wipers of the selector vswitchS202, are set, in accordance with the information transmitted from thecross-oiiice selector 3300K, for extending a connection to the outgoingline over which the message in the cross-oice unit must be transmittedto lreach its desired destination. The precedence switch S235 includesthree wipers and associated contact banks wherein the wipers thereof areset in accordance with the information transmitted from the cross-otceselector 3300X to mark the transmission precedence of the message to theoutgoing line circuit and to the designated cross-office assigner link.The cross-office assigner seylector switch S245 is made up of sevenwipers and associated contact banks wherein each set of contacts isconnected via a trunk, such as the trunk 260, to an individual one ofthe cross-oice-unit assigner links, such as the cross-oice assigner link300. The wipers of the selector switch S245 are set in accordance withthe setting of the wipers of the outgoing line selector switch S202 toengage the contacts extending a connection to the crossoflice assignerlink corresponding to the group of outgoing line circuits including theoutgoing line circuit terminating the called outgoing line.

' The cross-office assigner link circuit 300, shown in Fig. 3, includesa connect relay R330 and a release relay R340, and a selector switchS310 having associated there- 6 with a motor magnet MM311. The selectorswitch S310 includes seven wipers and associated contact banks thatcorrespond respectively to the contact banks of the crossoflice assignerselector switch in the cross-oice units.

The outgoing line nder link circuit 400, illustrated in Figs. 4 and 5,includes a precedence register 419 provided with a group of relays R420,R425, R430, R435, R440 and R445 and a group of diodes D423, D428, D433,D438, D442, and D447. Additionally, there is provided in the outgoingline iinder link circuit 400 a selector switch S410 having associatedtherewith a motor magnet MM415, and a group of control relays includinga start relay R510, an operate relay R520, a control relay R530, analarm relay R535, and a comparison relay R540.

In Fig. 6, there is illustrated a monitor unit 601 and a markabletransmitter 602 both of which are individual to the outgoing line L660.The monitor unit 601 includes a monitor tape 651 and a set of selectormagnets 650 which are selectively operative for perforating the tape.The markable transmitter 602 includes a set of transmitter contacts 610,a clutch magnet CM620 for operating the set of contacts 610 and a sendrelay R630 which is selectively operative to transmit signals over theoutgoing line L660.

The outgoing line circuit 800 includes a message counter 700 shown inFig. 7 provided with a units countv ing switch S710, a tens countingswitch S720, and a hundreds counting switch S730 which are selectivelyoperative to count the number of messages transmitted through theoutgoing line circuit and to mark the count lin the outgoing linecircuit. In addition, the outgoing line circuit S00, as shown in Figs.8, 9 and 10, includes a group of control relays, a start-of-messagesequence switch S8960 and an end-of-message sequence switch 881000. Thegroup of control relays includes a selector relay R810, a start relayR820, a transfer relay R830, a low resistance clutch relay R845, a highresistance clutch relay R850, a start-of-message end relay R860, astart-of-message relay R910, an end-of-message end relay R930, and anend-of-niessage relay R940. The start-of-message sequence switch S8960has associated therewith a motor magnet MM966 and includes ve -wipersand associated banks of contacts particularly adapted to sendstart-o-message information to the markable transmitter and monitor unitof Fig. 6, a sixth wiper and associated bank of contacts for controllingthe stepping operation of the motor maget MM966 and a seventh wiper andassociated bank of contacts for performing control operations within theoutgoing line circuit 800. The end-of-message sequence switch SS1000 isprovided with a motor magnet MM1012, tive sets of wipers and associatedbanks of contacts which are particularly adapted to send end-of-messageinformation to the markable transmitter and monitor unit of Fig. 6, asixth set of wipers and associated bank of contacts for controllingoperation of the motor magnet MM1012, and a seventh set of wipers andassociated banks of contacts for performing control operations withinthe outgoing line circuit 800.

The manner in which the above described apparatus is utilized in thecircuits of the invention will better be understood from theconsideration of the operation of the equipment in completing aconnection from the calling cross-oice-unit to a called outgoing line.

Initial operation of a cross-office unit in marking an outgoing linecircuit as called Assuming iirst that the cross-oiice unit 200 of Fig.2, has stored therein a telegraph message which is to be transmitted toa remote point via the outgoing line L660 the wipers 202A to 202G,inclusive, of the selector switch S202 are set to engage respectivelythe conductors 201A to 201G, inclusive, extending via the trunk 261 tothe outgoing line circuit 800 associated withthe outgoing line L660. Inconjunction with the setting of the wipers of the selector switch S202to engage the conductors extending to the outgoing line circuit 800, thewipers 245A to 254G, inclusive, of the cross-office assigner selectorswitch S245 are set to engage respectively the conductors 246 and 250 to255, inclusive, extending via the trunk 260 to the cross-ottico assignerlink 300 which is associated with the outgoing line nder link 400 havingaccess to the group of outgoing line circuits including the outgoingline circuit 800. The setting of the selector switch S245 may beaccomplished by stepping the wipers thereonC in unison with the steppingof the wipers of the selector switch S202. In this arrangement, assumingthat in the outgoing line selector switch S202 the iirst ten contacts ofthe banks extend to the individual outgoing line circuits of Group No. lincluding the outgoing line circuit 800, the rst ten contacts of thecross-oflice assigner selector switch are strapped to the conductors ofthe trunk 260 extending to the cross-oice assigner link 300 individualto the Group No. 1 of outgoing line circuits. Accordingly, the settingof the selector switches S202 and S245 is accomplished, as previouslyexplained, from the crossoffice selector switch 3300K and in a manner asexplained in the mentioned Stiles application.

It is assumed further that the wipers 235A to 235C, inclusive, of theprecedence switch S235 are set in accordance with the transmissionprecedence of the message stored in the cross-oice unit to indicate onany one of the conductors 201C, 201D and 201B the message precedence tothe outgoing line circuit 800. Specifically, and as pointed outpreviously, the message may have any one of a number of transmissionprecedences, including NM (deferred), R (routine), P (priority), OP(operational immediate), EM (emergency), and F (flash), named in theorder proceeding the lowest precedence to the highest precedence rating.For purposes of illustration the wipers of the precedence switch S235 inthe cross-otiice unit 200 have been set to indicate the message storedtherein as of a P or priority precedence. In addition, the test relayR3890X in the cross-otiice unit 200 is Vat this time operated asexplained in detail in the above mentioned Stiles application. Uponoperating the relay R3890X closes at contacts 3892X a circuit forextending battery potential via the winding of the test relay R3930X andthe wiper 202B of the selector switch S202 to the conductor 201Bextending via the trunk 261 to the outgoing line circuit 800.

Assuming further that the outgoing line 1.660 is at this time idle, theoutgoing line circuit 800 associated therewith is in its restored statewhereby ground potential is applied to the terminus of the conductor201B in the outgoing line circuit 800 via the contacts S67 and 823 andthe upper winding of the selector relay R810. Accordingly, a circuit iscompleted from ground potential via the upper high resistance winding ofthe selector relay R810 in the outgoing line circuit and via theconductor 201B and the winding or' the test relay R3930-X in thecross-otiice unit 200 to battery potential. Thereupon the relay R810 isoperated but due to the high resistance of the energized winding ofrelay R810 the relay R3930X is not operated.

In the outgoing line circuit 800 the relay R810 upon operating closes atcontacts S17 a circuit from ground potential via the contacts 867 andS23 and the lower winding of the relay R810 to battery potential formaintaining the relay R310 operated, closes contacts 811 for connectingthe conductor 201B of the trunk 261 to the conductor 801 in the trunk818 extending to the outgoing line finder link circuit 400, closescontacts 812 connecting the conductor 201D of the trunk 261 to theconductor S02 of the trunk 818, closes contacts 8113 for connecting theconductor 201C of the trunk 261 to the conductor 803 of the trunk 818,closes contacts 315 for applying ground potential to the conductor 305of the trunk 818,

and closes contacts 816 for connecting the conductor 201B of the trunk261 to the conductor 806 of the 818. At this time then the conductors201B, 201C,r 201D, and 201E extending from the cross-oce unit 2.00 areconnected in the outgoing line circuit 800 respectively to theconductors 806, 803, 802, and 801 extending tothe outgoing line finderlink circuit 400. In addition the conductor 805 extending to theoutgoing line finder link circuit 400 has ground potential appliedthereto in order to mark the outgoing line circuit as called and toinitiate. operation of the outgoing line finder link circuit 400.Further operation of the cross-office unit 200 and of the outgoing linecircuit 800 is conditioned upon seizure of the outgoing line circuit 800by the outgoing line inder link circuit 400 and upon seizure of thecross-otiice unit 200 by the cross-office assigner link 300.

Operation of the outgoing line Jinder link and cross-office assignerlink in seizing the outgoing circuit to the crossofce unit Consideringnow the operation of the outgoing line finder link circuit 400 inseizing the outgoing line circuit 800, ground potential applied to theconductor 805 in the outgoing line circuit 800 is extended in theoutgoing line finder circuit 400 via the conductor 411 and the windingof the start relay 510 to battery potential, whereby the start relayR510 is operated. Upon operating the start relay R510 completes atcontacts 511 a circuit extending from the wiper 410A of the selectorswitch S410 and via the contacts 416, 511 and 523 and the winding of themotor magnet MM415 to battery potential. The contacts of the bankassociated with the wiper 410A are connected via conductors, such as theconductor 804, to individual outgoing line circuits, such as the linecircuit 800, which conductors normally have ground potential thereon andare otherwise open lines when the associated outgoing line circuits areoperated to mark themselves as called. Ground potential applied at thecontacts to the wiper 410A is extended over the above traced circuitwhereby the motor magnet MM415 is energized to interrupt the circuit atcontacts 416, and thereby operate the motor magnet, it being of theoperate-upon-release type, so that the wipers of the selector switchS410 are stepped to engage the next set of contacts in the banks.Accordingly, the wiper 410A steps across the contacts of the associated1oank until a non-grounded contact is engaged whereupon the operatingcircuit for the motor magnet MM415 is interrupted.

Assuming that the conductor 804 terminated at the bank associated withthe wiper 410A is the first open conductor in the bank, the wipers 410Ato 410B, inclusive, engage the set of contacts terminating theconductors extending to the outgoing line circuit 800. During the sameinterval and in response to the operation of the start relay R510 thecircuit for operating the control relay R530 is interrupted at contacts512 to cause the timer arm 534 associated therewith to start oscillatingalternately interrupting and recompleting at the contacts 531 and 532the operating circuit for the slow-to-release alarm relay R535. In theevent that the control relay R530 is not reoperated within apredetermined period the timer arm 534 completely interrupts theoperating circuit for the alarm relay R535 whereby a short timethereafter the alarm relay restores and completes at contacts 537 acircuit for indicating faulty operation of the outgoing line tinder linkcircuit 400.

Assuming normal operation of the finder link 400, at the wiper 410B ofthe selector switch S410 a circuit is completed from ground potentialVia contacts 525, the wiper 410B, the conductor 806 extending to theoutgoing line circuit 800, the contacts 816, the conductor 201Bextending via the trunk 261 to the cross-otiice unit 200, the wiper 202Bof the selector switch S202, contacts 3S92X and the winding of the relayR3930X to battery potential whereby the relay R3930X operated, andwhereby, the upper winding of the selector relay R810 in the outgoingline circuit 800 is shunted by having ground potential applied to bothsides of the winding, The relay R810 is maintained operated through itslowerv Winding. In the cross-office unit 200 the relay R3930X uponoperating closes at contacts 216 a circuit for extending groundpotential via the wiper 245A of the selectory switch S245 to theconductor 246 extending via. the trunk 260 to the cross-office assignerlink 300, and closes at contacts 217 a circuit extending from resistancebattery Via the wiper 235A of the precedence switch S235, the conductor237 and the wiper 202D of the. selector switch S202, to the conductor201D extending via the trunk 261 to the outgoing line circuit 800. Inthe outgoing line circuit 800 resistance battery on the conductor 201Dis extended via contacts 812 and conductor 802 of the trunk 818 to theoutgoing line finder link circuit 400, and in the outgoing line iinderlink circuit 400 resistance battery of 48 volts on the conductor 802 isextended via the wiper 410D of the selector switch S8410 to the windingsof the relays R430 and.R435, whereby in this circumstance a circuit iscompleted from -.24 volts through the diode D438 and the winding of R435to the resistance battery so that the relay R435 is operated. y Uponoperating the relay R435 completes. at the con tacts 436 a circuitextending from batterypotential via the winding of the comparison relayR540, the contacts 422, 427, and 436 to the conductor 454 extending viathe trunk 450 to the cross-oice assigner link 300. Further operation ofthe outgoing line inder link circuit 400. is delayed pending theoperation of the cross-office assigner link 300 in seizing thecross-otlice unit 200. Reconsidering for a moment the operation of theout-Y, going line nder link 400 and particularly the operation ofv theprecedence register 419 therein, it is understood that the conductors201C, 201D, and 201B terminated in the outgoing line circuit 800 andconnected therein respectively to the conductors 803, 802 and 801extending to the outgoing line nder link circuit 400, extend not only tothe cross-oice unit 200 but to Vall cross-oce units having access to theoutgoing line circuit 800 and at any one time it is possible for each ofthe conductors` 201C, 201D and 201B to be marked with ground potential,or resistance battery indicating different transmission. preferences forthe messages stored in the cross-oice units. In this circumstance theprecedence register 419 will operate to mark out to the cross-officeassigner linkv the one of the different transmission precedences marked'thereto that is of the highest order. Specically, assuming that thereare three cross-oce units which are calling to the outgoing line circuit800 and -that the telegraph messages stored in the cross-oiice units arerespectively of a flash precedence, emergency precedence, andoperational precedence, the two cross-oiice units having the ashprecedence and emergency precedence messages will attempt to mark theconductor 201C with both ground potential and resistance battery and theother cross-office unit will mark the conductor 201D with groundpotential. As between the two cross-otlice units having the flashprecedence and the emergency precedence messages therein a circuit iscompleted from ground potential in the former cross-oce unit toresistance battery in the latter cross-office unit via the conductor201C and the total voltage drop is experienced acrossv the resistor 223in the latter cross-oice unit so that the conductor 201C is marked onlywith ground potential. Accordingly, when the conductors 201C and 201Dare both marked with ground potential which is extended via theconductor 803 and 802, respectively, to the outgoing line finder linkcircuit 400. In the outgoing line finder link circuit 400 groundpotential on the conductors 802 and 803 will cause the relays R420 andR430 in the precedence register 419 to be operated and due to thearrangement of the group of contacts associated with the relaysof theprecedence register 419 only the ash precedence conductor 451 will havebattery potential marked thereon thereby indicati' inga ash precedencemessage to be the highest precedence marked to the outgoing line finderlinkt Considering now the operation of the cross-oice assigner link 300in seizing the calling cross-office unit and assuming, in accordancewith the arrangement shown in thev drawings, .that the conductor 454extending thereto from the outgoing line finder link circuit 400 hasbatterypotential thereon, thereby indicating a priority precedencemessage to be the highest of the precedences marked, that. the conductor246 extending from the cross-oilice unit 200 via the trunk 260 hasbattery potential thereon thereby marking the cross-oice unit ascalling, and that the con ductor 252 extending from the cross-oice unit200 via the trunk 260 has ground potential thereon thereby in- 1dicating a message of priority precedence stored therein; a circuit iscompleted in the cross-office assigner link 300 from ground potential onthe conductor 246 via the con. ductor 320, the contacts 342 and 312, andthe Winding M ofthe motor magnet MM311 to battery potential Iwhereuponthe motor magnet MM311 is energized to interruptthe energizing circuitat the contacts 312 and is 'thereupon operated to step the wipers of theselector switch S310 in the counterclockwise direction to engage thenext contacts in the associated banks of contacts. Upon operating themotorv magnet MM311 closes contacts 312 to recomplete the operatingcircuit for the motor magnet.v

Accordingly, operation of the motor magnet MM311 in stepping the wipersof the selector switch S310 continues until the Wiper 310A`thereofengages the contact' terminating a conductor having groundpotential thereon, such as the conductor 246, whereupon a circuit iscompleted from ground potential on the conductor 246 Via the wiper 310A,the Winding of the connect relay R330, contacts-341 and the winding ofthe motor magnet MM311 to battery potential whereupon the connect re-llay R330 and the motor magnet MM311 are energized in series. The relayR330 operates but the motor magnet MM311 does not operate inasmuch as itis of the operateupon-release type.

f Upon operating the` relay R330 closes contacts 331 to 338, inclusive,thereby preparing at the contact 331 a circuitv for operating therelease relay R340 and completing at contacts 335 a circuit forextending battery potential marked' on the conductor 454 from the`outgoing line 'finder link 400 to the cross-oce unit 200. Speciiically,battery potential on the conductor 454 is extended via the contacts 335,the wiper 310B of the selector switch S310, the conductor 252 of thetrunk 260, the wiper 245D of the cross-ottico assigner selector switchS245 in the cross-oice unit 200, the wiper 235C of the precedence switchS235 and the winding of the marking relay R225 to ground potential.Thereupon the comparison relay R540 in the outgoing line finder circuit400 is operated in series with the marking relay R225 in the: cross-oflice unit 200 over the circuit including the conduc-I tor 454. Atthis time the cross-otlice assigner link 300i is seized to a cross-oceunit and specifically to the cross-` ofce unit 200 in Group No. l whichis calling to the; outgoing line circuit 800 and which has a messagetrans-- mission precedence marked therein corresponding to thetransmission precedence registered in the outgoing line finder link 400,and this condition of seizure is indicated in the outgoing line iinderlink 400 by the operation of the comparison relay R540 therein and isindicated in the cross-oice unit 200 by the operation of the marking.relay R225 therein.

In the outgoing line inder link 400, the relay R540 upon operatingcompletes at contacts 541 a circuit from ground potential extending viathe upper winding of the operate relay R520 to battery potential wherebythe relay R520 isl operated, applies at the contacts 542 a multipleground to the conductor 806 extending to the outgoing line circuit 800,vand completes at the contacts 543 a.' circuit for extending groundpotential via the conductor.

aanwas:

346 of the trunk 450 to the cross-omce assigner link 300through thewinding of relay R340 and contacts 331 to battery potential foroperating the release relay R340. therein. In the outgoing line linderlink 400, the consequent operation of the relay R520 closes at contacts52,1 a hold circuit therefor from battery potential via the upperwinding thereof, conductor 345 of the trunk 450 extending to thecross-oilice assigner link 300 and the contact 338 therein to groundpotential. In addition, the relay R520 interrupts at the contacts 523 apoint vin the circuit for operating the motor magnet MM415, closes atcontacts 524 an obvious circuit for reoperating the control relay R530to prevent the restoring of the alarm relay R535 and at contacts 525removes one of the multiple grounds from the conductor 8,06. Before;considering the consequent operation of the release. relay R340 in thecross-office assigner link 300, which controls release of the cross-oiceassigner link 300 and the outgoing line linder link 400 from the seizedcross-anice unit and seized outgoing line circuit, it is best 'toconsider the operation of the cross-oce unit 200 in respouse to theoperation of the marking relay R225 vin series with the comparison relayR540.

In the cross-ofhce unit 200 the operated markingrelay R225 completes atconctacts 226 a circuit from battery potential on the wiper 235C throughthe winding of the auxiliary marking relay R230 to ground potential,whereupon the relay R230 is operated. Upon operating the relay R230completes at the contacts 231 a circuit extending from ground potentialvia the contacts 241 and 231, the winding of the slave relay R220, thewiper 202A of the` outgoing line selector switch S202 and the conductor201A extending via the trunk 261 to the outgoing line circuit 800.Ground potential on the conductor 201A at the outgoing line circuit 800is extended through the resistor 819 and the winding of the startrelayR820 to battery potential whereby the slave relay R220 of'V thecross-otlice unit 200 isoperated in series with the "relay R820 ofv theoutgoing line circuit. The relay R220`upon operating closes at contacts222 a circuit for by-passing the contacts 231 whereby the relays R220and R820 are maintained operated irrespective of the operational stateof the auxiliary marking relay R230 in thecross-oilce unit. At thistime, the cross-oice unit 200 is` seized to the outgoing line circuit800 whereupon the cross-ofce assigner link 300 and the outgoing linefinder link 400 may be released from their connections. Release isfacilitated in the outgoing line circuit 800 by the operation of therelay R820 in opening at contacts 823 the circuit for maintaining therelay R810 operated through the lower winding thereof whereby contacts811, 812, 813, 815 and 816 are opened to interrupt in the outgoing linecircuit the connection from the calling cross-oiice units to theoutgoing line finder link and to cause the start relay R510 in theoutgoing line finder link to restore.

Release of cross-oce assigner link and outgoing line finder linkConsidering release of the crossoiiice assigner link 300 and theoutgoing line indcr link 400, it is recalled that at the time ofseizure, between the cross-oti-ice unit and the outgoing line circuit,the outgoing line inder link 400 has operated the start relay R510,` theoperate relay R520 and the comparison relay R540 and that the startrelay R510 is restored shortly thereafter when ground potential isremoved from the conductor 805 in the outgoing line circuit. Also atthis time the cross?. ofce assigner link 300 has the connect relay R330Yoperated and the motor magnet MM311 is Venergized but not operated andthe release relay R340 being of the slow-temperate type is operated ashort time 'thereafter as a consequence the operation of the comparisonrelay R540. ln response to the operation of .the release relay R340 thecontacts 341 are opened to restore relay R330 and to operate the motormagnet -MMrtl. itoistep:

the'wipers ofthe'selector switch S310 from the engaged contacts, thecontacts 342 are opened for disconnecting the start conductor 320 fromthe motor magnet and son` tacts 343 are closed for applying groundpotential to the conductor 345 extending to the outgoing line iinderlink 400. When `the lwipers of the selector switch S310 are steppedlfromthe engaged contacts ,theA circuit for operat'mg the. relays R225 andR230 of the cross-oice unit in series with the comparison relay R540 ofthe outgoing line finder link 400 via the conductor 454 is interruptedso that the named relays restore. At the same time that the motor magnetis operated the connect relay R330 restores to open contacts 331 to 338,inclusive, and

thereby interrupting at contacts 331 the operating circuit for therelease relay R340. Shortly thereafter the relay R340 restores and openscontacts 343 for removing ground potential from the conductor 345 overwhich the operate-relay R520 in the outgoing line finder link` 400 isoperated so that R520 restores. These restoring operations take placeduring the interval that the crossotEce lunit is being seized to theoutgoing line circuit so that at approximately the same time that theoperate relay R520 is restored, the start relay R510 is restored by theremoval of ground potential from the conductor 80S in the outgoing linecircuit 800 and the operated precedence register relay R435 is restoredby interruption of contacts 812 in the outgoing line circuit 800.Accordingly, all of the relays in the cross-oiiice assigner link 300 andthe outgoing line inder link 400 are restored to normal, groundpotential is applied to the wiper 410A of the selector switch S410 bythe conductor 804 so that at this time the cross-oice assigner link 300and the outgoing line finder link 400 are idle and ready to be operatedrespectively by associ-ated calling crosso'tlice units and by associatedcalled outgoing line circuits, Additional-ly, at this time the relaysR3930X and R225 and R230 in the cross-oice unit 200 are restored, theformer relay by the removal of ground potential from the conductor 201Bat the contacts 816 in the outgoing line circuit and the latter tworelays by the release of the cross-oice assigner link 300 from the trunk260 extending from the cross-cnice unit. Further operation of thecross-oiiice unit 200 and outgoing line c'ircuit'800is directed totransmitting telegraph signals correspondingv yto the telegraph messagestored in the cross-cnice unit 200 over the outgoing line L660.

Operation of the cross-office unit and outgoing line crcuit intransmitting the telegraph message vAs is described in detail in thepreviously mentioned Stiles application, Serial No. 260,854, filedDecember l0, 1954, the cross-office unit is at this time operated withthe clutch magnet M3425X restored and the crossoiice tape, having thetelegraph message perforated 4thereon, vin position with regard to thetransmitter sensing contacts 3490X thereof so that the start-of-messagein-v dication thereon is advanced beyond the contacts 3490K andthechannel or incoming line identiiication characters thereon preceding thebody of the telegraph message on the tape are positioned immediately infront of the sensing contacts 3490X and will be transmitted when theclutch magnet M3425X is again operated.

Considering iirst the operation of the outgoing line circuit i800 infurthering the transmission of the stored telegraph message, the relayR820 therein, which was operated in response to seizure of the outgoingline circuit Vbythe cross-ofce unit 200, in addition to opening contacts823 for restoring relay R810 closes at contacts 824 a' Ycircuitextending from battery potential via the low resistance clutch relayR845 and the series connected high resistance clutch relay R850,contacts 945, 93S, and 824, the-conductor 201F of the trunk 261extending to the cross-office unit 200, the wiper 202F of the outgoingline selector switch S202 and the winding of the` 13 the relays R845,R850 and the magnet M3425X are energized in series and the relay R845and the magnet M3425X are operated, the relay R850 being operated ashort Yperiod thereafter inasmuch -as it is of a high re-y nection fromthe sensing contacts M3490X in the cross! oce unit via the wiper 202G ofthe selector switch 8202 the conductor 201G extending via the trunk26110 the outgoing -line circuit 800, the contacts 825 and 840, theresistance 843, the contacts 844 -to the conductor 808 extending via thetrunk 829 to the monitor unit 601, and the selector magnets 658 ltobattery potential. Accord# ingly, the selector magnet 650 in the monitorunit 601 is prepared to perforate the tape 651 fin accordance with theincoming line identity characters stored in the crossoce unit 200 lassensed by the sensing contacts 3490X under control of the clutch magnetM3425X.

The clutch relay R850 in the outgoing line circuit 800 upon operatingcloses at contacts 853 a circuit for operating the start-of-messagerelay R910 from ground potential via the contacts 853 and 863 and theupper winding of the relay R910 to battery potential. The' relay R910upon operating closes at contacts 915 a circuit extending from groundpotential via the contacts 967, 915, 968 of the olf-normal switch-ON965and the the sequence switch SS960 to the conductor 963 extendf ing viathe trunk 829 to the markable transmitter 602 and therein through thewinding of the clutch magnet CM620 to battery potential, whereby themagnet CM620 is operated when the wiper 960G engages a contact havinggroundpotential thereon. Further, the operated relay R910 closescontacts 919 for completing a hold circuit therefor from groundpotential via the contacts 868, 936 and 919, and closes contacts 920 forcompleting a circuit from battery potential via the winding of the motormagnet MM966, the contacts 920, the conductor 962 extending via thetrunk 829 to the markable transmitter 602 to the individual contacts 611of the set of transmitter contacts 610. Y

Considering for a moment the cooperative operating arrangement betweenthe set of transmitter contacts 6,10 in the markable transmitter 602 andcertain of the banks of contacts in the start-of-message sequence switchSS960 in the outgoing line circuit 800, the set of transmitter contacts610 includes seven individual contacts 611 to 617, inclusive, of whichthe contacts 611 and 613 to 617, inclusive, are normally opened and thecontacts 612 are normally closed. The set of contacts are operated fromthe clutch magnet CM620 through continuous cycles wherein during eachcycle the normally closed contacts 612 are opened and the normallyopened contacts 611 are closed during the period of the cycle andwherein the contacts 613 to 617, inclusive, are closed and opened one ata time and consecutively during Vthe period of the reading cycle. Theindividual contacts 611 upon closing complete a connection from groundpotential to the conductor 962 of the trunk 829, and the contacts 612upon opening interrupt a connection between the conductor 809 of thetrunk 829 and one terminal of the winding of the send relay R630.Additionally, the contacts 613 to 617, inclusive, upon closing completeconnections from the conductors 961A to 961B, inclusive, respectively,of the trunk 829, to the one mentioned terminal of the Winding of thesend relay R630.

In the outgoing line circuit 800 the conductors 961A;

to 961B, inclusive, of the trunk 829 are terminated re# spectively atthe wipers 960A to 960E, inclusive, of the start-of-message sequenceswitch SS960. Each of the banks associated with the wipers 960A to 960B,inclusive, include 25 contacts and are connected to ground potential inaccordance with the standard telegraph code shown in Fig. l2, totransmit to the markable transmitter certain information as shown inFig. 13, including a startof-message designation, letters identifyingthe outgoing line circuit, and numerals corresponding -to a count of themessages transmitted during a given transmission 'period over theoutgoing line L660. A wiper 960F is asso# ciated with the sequenceswitch SS960 for the purpose of selectively operating certain of therelays in the outgoing line circuit 800, and the wiper 9'60G which, aspreviously pointed out, is connected to the conductor 963 of the trunk829 for the purpose of controlling operation of a clutch magnet CM620 inthe markable transmitter 6012.

`Considering now operation of the markable transmitter 602 from theoutgoing line circuit 800, ground potential applied to rthe conductor809 at the contacts 842 is extended via the trunk 829 to the markabletransmitter 602, through the normally closed individual contacts 612thereof, the winding of the send relay R630, and Via the conductor 807of the :trunk 829 to the outgoing line circuit 800 and through thecontacts 837 to resistance battery whereby the send relay R630 isnormally operated.` However, when the clutch magnet CM620 is operatedfrom ground potential by the wiper 960G of the sequence switch SS960being stepped from its home position into engagement with the first ofits contacts, the set of trans` mitter contacts 610 in the markabletransmitter 602 are operated in a manner as previously explained tocause the send relay to restore and to be thereafter selectivelyoperated and restored from ground potential marked to the conductors961A to 961B,` inclusive, by the wipers 960A to 960B, inclusive, of thesequence switch SS960;y Accordingly, as the wipers of the sequenceswitch SS960,

are stepped across the first l5 contacts thereof the rst 15 characterslisted under column SS960, of Fig. 13, are transmitted over the outgoingline L660 and during the same period the selector magnets 650 of themonitor unit 601 are operated from the sensing contacts 3490X in thecross-oce unit 800 over the previously traced pathV to perforate thetape 651 with identityv information Are garding the incoming line overwhich the telegraph message was received in the switching center. v

At the end of this period the tape in the cross-office unit 200 isadvanced so that the body of the telegraph message is immediate to thesensing contacts 3490X, and thewipers of the sequence switch SS960 areadvanced into engagement with Vthe 16th contacts in the associated bankswhereupon ground potential for operating the clutch magnet CM620 in themarkable transmitter 602 is removed from the conductor 963 at the wiper960G. At the same time the wiper 960F of the sequence switch CC960completes a circuit from ground potential via the contacts 912, thewiper 9601:", the 16th contact of the associated contact bank, thecontacts 846, and the upper winding of the transfer relay R830 tobattery potential,

contacts 873, the winding of R870 and contacts 921,v

whereby contacts 871 are closed to maintain relays R845 and R850operated and contacts 872 are opened to ref,

move operating battery from tne conductor 201F extending to the clutchmagnet M3425X in the cross-oice unit' 200 so that the sensing action ofthe sensing contacts 3490X therein is terminated.

Additionally, the transfer relay R830 upon operating closes contacts836, 838, 839 and 841, and opens contacts'VV 837, 844, 840v and 842thereby 'disconnecting the moniz.

tor unit 601 from the sensing contacts 3490K in the cross-oflice unit200 and connecting the monitor unit 601 in series with the send relayR630 and the markable transmitter 602 to the sensing contacts 3490K.Specifically, a circuit is completed from battery potential via theselector magnet 650 in the monitor unit 601, the conductor S08 of thetrunk 829 extending to the outgoing line circuit 800, the contacts 833and 836, 'the conductor 807 of the trunk 829 extending to the markabletransmitter 602, the winding of the send relay R630, the normally closedcontacts 612 of the transmitter contact set 610, the conductor 309 ofthe trunk 329 extending to the outgoing line circuit 800, the contacts841, S39 and 325, the conductor 201G of the trunk 261 extending to thecrossoflice unit 200, the wiper 202G of the selector switch S202, and toground potential via the set of contacts 3490X. Further, the relay R530upon operating closes contacts 833 for extending ground potential to thewiper 960G of the sequence switch SS960. Thus at this time the identityinformation recorded on the tape in the crossoice unit 200 has beentransferred to the monitor unit tape 651 in the monitor unit 601 and theoutgoing line 1.660 has had transmitted thereover the start-of-messagedesignation, whereupon transmission in the cross-office unit 200, isinterrupted and the monitor unit 601 is con nected in series with themarkable transmitter 602' and the send relay R630 so that the outgoingline circuit identity signals and the message count number may besimultaneously ytransmitted over the outgoing line L63@ and perforatedin the tape 651 of the monitor unit 601.

Considering now the operation of the outgoing line circuit 800 to causethe outgoing line circuit identity characters and the message countnumbers to be sent over the outgoing line and recorded on tape of themonitor unit 601, as previously pointed out, the relay R830 uponoperating closes at contacts 833 a circuit for'extending groundpotential to the wiper 960G of the sequence switch S8960, which groundpotential is extended over the conductor 963 to the markable transmitter602 causing the clutch magnet CM620 therein to be operated. The wipersof the sequence SS960 then step consecutively from the 16th Contactthrough the 21st contact in a manner as previously explained to causethe outgoing line circuit identity characters listed for the 16th to21st switch points inclusive, under the column S8960 of Fig. 13, to betransmitted over the outgoing line L660 and to be perforated in the tape651 of the monitor unit 601.

Thereafter numerals corresponding to the message count registered in theoutgoing line circuit 800 are transmitted via the wipers of the sequenceswitch S5960. Specifically, when the Wipers 960A to 960B, inclusive, arestepped from the 21st contacts to engage the 22nd contacts of theassociated contact banks, connections are completed thereover,respectively, to the wipers 730A to 730B, inclusive, of the hundredscounting switch S730 whereby the number marked therein is transmittedto` the markable transmitter 602. Thereafter, the wipers 960A to 960B,inclusive, of the sequence switch S5960 engage the 23rd, contacts of theassociated banks thereby completing connections respectively to thewipers 720A to 720E, inclusive, of the tens counting switch S720 wherebythe number marked therein is transmitted to the markable transmitter602. Thereafter, when the wipers 960A to 960E, inclusive, engage the24th con tacts in the associated contact banks connections are completedrespectively to the wipers 710A to 710B, inclusive, of the unitscounting switch S710, whereby the number marked therein is transmittedto the markable transmitter 602. When the wipers of the sequence switchS8960 engage the 25th contacts in the associated Contact bank a circuitis completed from ground potential via the contacts 912, the wiper9601?, the 25th contact of the associated contact bank and the windingof the motor magnet MM716 to battery potential whereby the motor magnetMM716 is energized and is operated thereafter,

numerals.

when the circuit is interrupted by the wipers of the` sequence switchS5960 stepping from the 25th contact to the -horne position, so that thewipers 710A to 710F, inclusive, of Athe units counting switch S710 aresteppedV in a counter-clockwise direction to engage the next con-v tactin the associated banks. At the same time, when the wipers of thesequence switch S8960 step from the 25th contact to their home position,a circuit is oompleted from ground potential via contacts 912, the wiper960F, the home contact of the associated contact bank, contacts 832 andthe upper winding of the start-ofmessage end relay R860 to batterypotential whereupon the relay R860 is operated to indicate in theoutgoing line circuit 800 that the operation of the sequence switc S8960is completed.

Referring for a moment to the operation of the counting switches S710,S720 and S730, it is understood that when the wipers of the unitscounting switch S710 is stepped into engagement with the 9th contactthereof a circuit is completed for energizing the motor magnet MM726associated with the tens counting switch S720, which motor magnet isoperated when the wiper 710F is stepped from the 9th contact associatedtherewith to the 10th contact whereupon the wipers of the tens countingswitch S720 is stepped in a counter-clockwise direction to engage thenext contacts in the associatedcontact banks. The wiper 720F of the tenscounting switch S720 performs the same control operation with regard tothe motor magnet MM736 of the hundreds counting switch S730 at the 10thcontact positon thereof, so that the wipers of the units counting switchS710 are stepped through ten contact positions for keach contactposition that the wipers of the tens counting switch S720 are stepped,the wipers of the tens counting switch S720 are stepped through tencontact positions for each contact position that the wipers of thehundreds counting switch S730 are stepped, thereby to register a countof the number of messages transmitted over the outgoing line.

Referring again to the operation of the outgoing line circuit 800, inresponse to the operation .of the startof-message end relay R860 anobvious hold circuit is completed therefor at the contacts 861 and theoperating circuits for the start-of-message relay R910 are interruptedat the contacts 863 and 868, whereby the latter relay restores. Uponrestoring the relay R910 interrupts at contacts 916 and 920 theconnections between the markable transmitter 602 and thestart-ofrnessage sequence switch S5960, and interruptsatthe contacts 921the circuit for maintaining the control relay R870 operated. Thereafter,the relay R870 restores and again completes at the contacts 872 thecircuit for operating the clutch magnet M3425X of the cross-,oiice unit200 in series with the 10W resistance and high resistance clutch relaysR845 and R850 of the outgoing line circuit 800. Thereupon the cross-oceunit 200 and the outgoing line circuit 800 are prepared to cause thebody of the telegraph message stored in cross-oice unit 200 to betransmitted over the outgoing line L660 and -to be perforated on thetape 651 of the monitor unit 601.

Recapitulating for a moment, it is clear from the foregoing that at thistime the tape 651 of the monitor unit 601 has recorded therein incomingline identity information transferred thereto from the tape in thecrossoice unit 200, the outgoing line identification letters and themessage count numerals, and the outgoing 4line L660 has had transmittedthereover the start-of-message letters, the outgoing line identityletters, and the message count Accordingly, processing of the messagehas advanced to the state that the circuits are prepared to transmitover the outgoing line 1.660, and to record in the tape 651 yof themonitor unit 601 the characters in the body of the telegraph messagewhich are recorded` 0n the tape in the :cross-cnice unit 200.

Considering now the operation `of the cross-oice unit 200 and theoutgoing line circuit 800 in transmitting the characters of thetelegraph message over the outgoing line 1.660, it is assumed that atthis time the tape in the crossoce unit is advanced through the sensingcontacts 3490K so that the contacts are prepared to sense the charactersin the body of the telegraph message. Accordingly, when the clutchmagnet M3425X in the cross-oice unit 200 is again operated in serieswith the clutch relays R845 and R850, the sensing contacts 3490K areoperated to cause ground pulses corresponding tothe characters in thebody of the telegraph message to be transmitted over the conductor 201Gof the trunk 261 to the outgoing line circuit 800, the previously tracedseries connection including the conductor 809 of the trunk 829, theindividual contacts 612 of the set of transmitter contacts 610 in themarkable transmitter 602, the winding of the send relay R630, theconductor 807 of the trunk 829 extending to the outgoing line circuit800, and the conductor 808 of the trunk 829 extending through magnet 650to battery potential in the monitor unit 601. Accordingly, the sendrelay R630 and the selector magnet 650 are operated in series inaccordance with the ground pulses transmitted from the set of sensingcontacts 3490K whereby the characters in the body of the telegraphmessage are transmitted over the outgoing line L660 and are perforatedin the tape 651 of the monitor unit 601. In this manner the set ofcontacts 3490K in the cross-oiice unit 200 continues to read andtransmit ground pulses corresponding to the characters in the body ofthe telegraph message until the endof-message designation is detected inthe tape reader thereof and for the predetermined number of readingcycles thereafter required to permit all of the characters in the bodyof the telegraph message to be transmitted over the conductor 201G.Thereupon the `control relay R3830X is operated in the manner asexplained in the above mentioned Stiles application to interrupt atcontacts 241 the circuit for maintaining the slave relay R220 of thecross-ohce unit 200 operated in series with the start relay R820 of theoutgoing line circuit 800 whereupon the slave relay R220 and the startrelay R820 restore.

At this time then, operation of the cross-oiiice unit 200 intransmitting the message stored therein over the outgoing line L660 iscompleted, the test relay R3890X therein is restored in a manner as isexplained in detail in the copending Stiles application therebyinterrupting contacts 3892K to remove battery potential from theconductor 201B of the trunk 261, whereupon the cross-oice unit isprepared to be released and will be completely released and restored tonormal and prepared to receive therein another telegraph message fortransmission over an outgoing line when the connections to theconductors 201F and 201G are interrupted in the outgoing Yline circuit800.

Operation of the outgoing line circuit in releasing the crossolce unitand in transmitting the end-of-message characters In the outgoing linecircuit 800 the restoration of the start relay R820 interrupts atcontacts 824 and 825, respectively, the connections therein to theconductors 201F and 201G extending to the cross-otiice unit 200 wherebythe cross-oice unit is completely released and prepared to receive othertelegraph messages. The openingof the contacts 824 also interrupts theoperating circuit for the clutch magnet relays R845 and R850 whereby therelay R845 restores immediately and the relay R850, it 4being of highresistance type, restores shortly thereafter. During the periodimmediately preceding the restoration of the relay R850, the start relayR820 closes at contacts 821 one point in the circuit for operating theend-of-message relay R940 and closes at the contacts 826 one point inthis circuit for applying ground potential to the conductor 809 of thetrunk 829- extending to the markable transmitter 602. Thereafter, whenthe relay R850 restores there is completed at the contacts 852 a circuitextend- 18 ing from ground potential via the contacts 821, 852, 862 and913 and the winding of the relay R940 to battery potential whereby theendof-message relay R940 is operated, and there is closed at thecontacts 854 a circuit extending from ground potential via the contacts854, 826, '839 and 841, and the conductor 809 of the trunk 829 extendingto the markable transmitter 602 to complete the previously tracedcircuit for operating the send relay R630 therein and the selectormagnet 650 in the monitor unit 601 in series. At this time the outgoingline circuit 800 is prepared to cause certain end-of-message informationto be transmitted over the outgoing line L660 and to cause the tape 650of the monitor unit 601 to be perforated in accordance therewith. i

The end-of-message relay R940 controls. operation of the end-of-messagesequence switch SS1000 in applying to the outgoing kline 1.660 and tothe selector magnets 650 of the monitor unit 601 telegraph signals inthe standard telegraph code of Fig. 12 corresponding to that informationshown under column $81000 in Fig. 13, and including letterscorresponding to the outgoing line identity, numerals corresponding tothe time of day, and characters corresponding to the end-of-messagedesignation followed by certain line feed and control characters whichmay be varied to accommodate the telegraph system and the variousequipment included in the telegraph system. Before considering thefunctions of the sequence switch $51000 it is well to consider theconstruction of the sequence switch 881000 and the manner in which thevarious wipers thereof are connected to the trunk 829 extending to themarkable transmitter 602 and to 'the Yvarious relays in the outgoingline circuit 800.

Referring specifically to the end-of-message sequence switch $51000there is included therein six pairs of Wipers and associated contactbanks including the wipers 1010A to 10101:, inclusive, and Wipers 1011Ato 1011F, inclusive, wherein the wipers having like sutx letters arearranged in pairs. Each bank of contacts includes 25 individual contactsand the Wipers of each pair are connected in parallel and are arrangedwith regards to the associated contacts so that each pair of wipers andassociated contact banks effectively comprises a 50 point switch. Thewipers 1010A and 1011A are connected in. parallel to the conductor 961Aof the trunk 829; the wipers 1010B and 1011B are connected in parallelto the conductor 961B of the trunk 829; the wipers 1010C and 1011 areconnected in parallel to the conductor 961C of the trunk 829; the wipers1010D kand 1011D are connected in parallel to the conductor 961D of thetrunk 829; and the wipers 101015 and 1011E are connected in parallel tothe conductor 961D of the trunk 829. The trunk 829, as previouslypointed out, extends to the markable transmitter 602 and tocorresponding individual contacts in the set of transmitter contacts 610thereof. The wipers 1010F and 1011F are connected in parallel via thecontacts 942 to the conductor 963 of the trunk 829 extending to theclutch magnet CM620 of the markable transmitter 602 for selectivelyoperating the clutch magnet and the set of transmitter contacts 610associated therewith. The motor magnet MM1012 associated with thesequence switch SS1000 is operated during each reading cycle from theindividual contacts 611 of the set of contacts 710 and via the conductor`962 of `the trunk 829 in a manner as will be described in detailhereinafter.

Considering now the operation of the outgoing line circuit 800 intransmitting the end-of-message Yinformation to the markable transmitter602, the relay R940 upon operating closes at contacts 948 a4 circuitvextending from ground potential via the contacts 1013 and 948, contacts1017 of the oit-normal switch ON1015 through the winding of the motormagnet MM1012 to battery potential, whereby the motor magnet MM1012 isenergized to open the circuit at the contacts 1013 and thereupon isoperated to step the wipers 1010A to 101011, inclusive, of thesequenceswitch SS1000 one

